Lymphocytic choriomeningitis virus (LCMV) is a neglected rodent-borne arenavirus,
primarily spread by common house mouse species. Acquired human infections range from
asymptomatic to mild flu-like symptoms and self-resolving neurological diseases. In
contrast, intrauterine LCMV infection is associated with high mortality and morbidity.
Infection of the fetus often leads to fetal death, and surviving fetuses may develop
vision impairment and central nervous system developmental disorders. LCMV is mainly
diagnosed by serological methods using in-house indirect immunofluorescence assays.
LCMV nucleic acid is detected by the nested RT-PCR method and confirmed by Sanger
sequencing. In Hungary, 23 acquired lymphocytic choriomeningitis cases were diagnosed
between 2017 and 2023. Ten out of 23 confirmed patients proved to be positive by the
PCR method. Two cases of intrauterine LCMV infections were detected in 2019 and 2021,
respectively. The IgG antibody titers measured in the infant’s serum samples were
much higher than the IgG titers of the maternal serum samples. Both IgM and IgA antibodies
were detectable in the infants’ sera. As the microbiological diagnosis of LCMV is
rather challenging and the symptoms are very similar to the clinical picture of other
common teratogenic pathogens such as cytomegalovirus or Toxoplasma gondii, intrauterine
LCMV infections might still be underdiagnosed.